1. Field of the Invention
The field of the invention relates to identification systems generally, and more particularly to certain new and useful advances in micro-power credential readers, of which the following is a specification, reference being had to the drawings accompanying and forming a part of the same.
2. Discussion of Related Art
A credential is plastic card or other device that is configured to interface with a credential reader to identify a particular individual and one or more privileges associated with the individual and/or with a class to which the individual belongs. One example of a credential is an employee badge that is configured to open one or more locked doors and/or to disarm a security system.
Present credential readers use several techniques to detect the presence of a credential. One such technique is to energize the sense field (or “read field”) on a continual basis to immediately read the credential when it is presented to the credential reader. The continual field technique is an industry standard, used across many types of credential readers. Another technique is to energize the sense field on a periodic basis (as with a burst of RF energy). A problem with both the continual field technique and the periodic field technique is that each technique requires far too much electrical power to be used in a battery-powered credential reader.
Another technique, perhaps more suitable to a battery-powered credential readers, emits infrared light and then detects the infrared light that is reflected off the credential. A problem with the infrared technique is that it still consumes too much power (e.g., milliamps), and thus shortens battery life. Another problem with the infrared technique is that it is susceptible to contaminates that may intentionally or unintentionally obscure the infrared light source and/or the infrared light detector.
A solution is needed that provides a battery-powered credential reader having a micro-power proximity detector configured to maximize battery life.